The United States Mint is where our coins are made. But how do you know which branch made it? That's where mint marks come in.

Before the United States Mint

  During the years between the signing of the Declaration of Independence in 1776 and the adoption of the Constitution on September 17, 1789, the Articles of Confederation was the prevailing system of government. States were mostly independent and there was little federal control and certainly no unified national coin or currency system. Great Britain held back its silver coinage insisting the Colonies send silver to them. To fill the void, barter was common while states created their own sets of coinage and fiat currency that were hard to understand for everyday exchange. The Spanish silver dollar known as the 'piece of eight' was the most common coin used throughout the Colonies, but with different exchange rates.

  Once the Constitution was passed in 1789, the Coinage Act of 1792 changed all that by "...establishing a mint, and regulating the Coins of the United States." It also created the United States dollar that would have "...the value of a Spanish milled dollar as the same is now current." The Coinage Act also established decimal accounting where units are related to the power of 10, the first national coinage to do so. It also established the first official Mint in Philadelphia, the nation's capital at that time.

Philadelphia Mint (1792-present): Mint Mark, None until 1980 with exceptions.

The first United States Mint was an agency of the Department of State with David Rittenhouse, surveyor, astronomer, clockmaker and member of the American Philosophical Society, appointed by President George Washington as its first director. The Philadelphia Mint was the first federal building constructed under the Constitution.

The day before, Rittenhouse hand-struck several pattern coins (test coins) called the Nova Constellatio to test the new equipment using silver melted down from flatware contributed by Martha Washington. Rittenhouse then gave these first pattern coins to President Washington. Other pattern coins, 1,500 half dimes and dimes (aka dismes), were struck which were eventually released into general circulation.

The Philadelphia Mint used no mint mark until 1980 when 'P' was added to all coins produced there. Exceptions were made by adding the mint mark 'P' to the Jefferson nickel minted in 1942-1945 to show that the nickel was exchanged for an alloy of copper, 35 percent silver and manganese and the Susan B. Anthony dollar coin minted from 1979-1981 and again in 1999.

Three branch offices of the United States Mint were opened in 1838 to include one in Charlotte, North Carolina. It primarily processed gold dust and gold nuggets mined at the Reed Gold Mine in Cabarrus County, 20 miles northeast of Charlotte, North Carolina.

Before the Charlotte Mint opened, all gold had to be transported to the Philadelphia Mint for assay and smelting into gold bars and coins making the 540-mile trip overland (about 30 days) through dangerous Cherokee Indian Territory. It took months for the raw gold to be minted into coins.

The Charlotte Mint operated until the outbreak of the Civil War in 1861 when it was closed as an official United States Mint. After the War ended it was reopened as an assay office only in 1867, but finally closed in 1913.

The gold coins minted at the Charlotte Mint include the $1, $2, $3 gold coins and the Liberty Head Half Eagle gold coins, among others.

Dahlonega Mint:

The second branch Mint opened in 1838 was the Dahlonega Mint, located about 75 miles north of Atlanta. Gold was found in the Cherokee Indian Territory nearby in the 1800s, about the same time that gold was found near Charlotte. Prospecting turned to commercial gold mining and travel to Philadelphia became more dangerous through the mountains.

The Dahlonega Mint processed gold deposits into official legal tender gold coinage for the Southern states. Coins struck were the gold dollar, $2½ quarter eagle, $3 gold coin in 1854 only, and $5 gold Liberty Eagle gold coins with a mint mark of 'D'. Because of the relatively few gold coins minted, less than 1 percent of the gold coins minted at the Dahlonega Mint have survived.

The Dahlonega Mint was seized by the Confederate States of America and produced a limited number of 1861 gold dollars and gold eagles, but without the 'D' mint mark until it was abandoned later that year.

Gold nuggets and gold dust mined in the Deep South and along the Western frontiers needed to be assayed and struck into legal tender coinage. For that, the United States Mint opened the third Mint branch in 1838 at the most strategic port in the Americas, New Orleans. Already handling all manner of domestic and foreign trade, the New Orleans Mint served as an official Mint from 1838 until 1861 when the State of Louisiana seceded from the United States.

During the first month of the takeover of the New Orleans Mint by the Confederate State of Louisiana, U.S. gold coins using the same dies continued to be produced for its treasury and later for the Confederate government. The gold ore ran out after the first month and the Mint remained under the Confederacy until it was recaptured by U.S. forces the following year.

The New Orleans Mint was back in operation from 1879 until it finally closed in 1909 producing $1 to $20 gold eagle coins and the silver Morgan dollar coins, among others.

San Francisco (1854-1954, 1968-present): Mint Mark 'S'

Sutter's Mill in Coloma, California, was the site of a gold discovery by James Marshall in 1854 marking the beginning of the California Gold Rush that lasted until 1855. But with the large influx of prospectors during the period and the amount of gold entering the monetary system, a new branch Mint was established in San Francisco in 1854 to handle the large influx of gold.

The operation quickly outgrew the original building and a new building of granite and sandstone became the second Mint building in 1874. This was one of the few buildings that survived the devastating 1906 San Francisco earthquake virtually intact with about a third of the United States gold reserves undamaged.

Only proof and commemorative coins have been struck at the San Francisco Mint when minting resumed in 1968 with the exception of some circulating coins, the Susan B. Anthony dollar (with the 'S' mint mark) and some pennies during the 1980s (with no mint mark). In 1962 the Mint was officially downgraded to an assay office, but regained its official Mint status in 1988.

Carson City, Nevada (1870-1886, 1888-1893): Mint Mark 'CC'

While there was a gold rush elsewhere, silver ore was discovered in large quantities in 1859 at Virginia City, Nevada, not far from Reno, in the Sierra Mountains. It was named the 'Comstock Lode' for Henry Comstock who neither discovered nor profited from the discovery.

There was a call for an official Mint to process the silver and gold ore into legal tender coins as early as 1858, because the closest Mint was a dangerous 250-mile trip over mountains to San Francisco. By 1863 a new mint was finally authorized, but didn't become operational until 1870 when it was located at Carson City, Nevada, about 32 miles south of Reno. The Mint operated until 1886 striking mostly silver coins from the Comstock Lode along with some gold coins as well. The Mint reopened in 1888 and closed in 1893.

Altogether, the Carson City Mint struck 50 issues of silver coins, including the seated Liberty dime, quarter, half-dollar and dollar, the Trade and Morgan dollars and a 20-cent piece along with 57 issues of gold coins including the $5 half eagle, the $10 gold eagle and the $20 double eagle, according to a Wikipedia entry, with many of the coins considered rare.

This may be the only time a private commercial mint became an official U.S. Mint. Clark, Gruber and Co. established a commercial brokerage in Leavenworth, Kansasm, in 1859 with a branch office in Denver opening a year later, mostly to assay the gold being found in the Pike's Peak area near Colorado Springs, Colorado. The company struck its own $2.5, $5, $10 eagle and $20 double eagle gold coins with their company name on the reverse until the operation was bought by the U.S. government in 1863.

Although, it opened as the U.S Denver Mint in 1863, the facility was used only as an assay office to smelt gold into individual bars and returned to the miner. No coins were actually struck until a new facility was opened in February 1906. The $5 half eagle, $10 eagle and the $20 double eagle gold coins were the first coins with the 'D' mint mark. Some silver coins were also minted here for the first time.

The Denver Mint continues to produce coins in general circulation, mint sets and commemorative coin sets, all with the 'D' mint mark, and is considered the biggest producer of legal tender coins in the world, according to a US-Mint.info.

While the mint marks for the Dahlonega and Denver Mints are identical, neither was operating at the same period in time.

Manila, The Philippines (1920-1922, 1925-1941): Mint Mark 'M'

Shortly after the Treaty of Paris was signed in 1898 ending the Spanish-American War, the United States took possession of several Spanish territories in the Pacific to include The Philippines. One of the properties was the Philippine Mint originally operated by the Spanish to produce local coinage. After U.S. possession, silver coins continued to be minted under U.S. supervision that were similar to the Spanish silver peso along with the one, ten, twenty and fifty centavo coins.

In 1903, the San Francisco Mint produced silver coins for the Philippines with a small 'S' mint mark, but by 1908 began minting all general circulation coins as well until 1920. In that year, the U.S. Mint created the Manila Mint, the only Mint outside the continental United States, to produce all coinage using the old Spanish Mint facilities until 1922 without a mint mark.

The Manila Mint produced no coinage from 1923 until it reopened in 1925, again producing its own currency, but this time adding an 'M' as its own mint mark. The Manila Mint was closed permanently after the Japanese occupation in 1941 during World War II.

West Point, NY (1988-present): Mint Mark 'W'

Officially known as the West Point Mint Facility since 1988, the former West Point Bullion Depository began storing silver in 1937 near the West Point Military Academy with the nickname "The Fort Knox of Silver," although some gold was stored in the facility as well. It is the only bullion depository to become an official U.S. Mint.

The 1984 Los Angeles Olympic Games $10 gold commemorative coin was the first coin minted featuring the 'M' mint mark and the first official legal tender gold coin issued in the United States since 1933. Several other commemorative coins featuring the 'W' mint mark include the 1996 Roosevelt dime, the 2015 Roosevelt dime and $1 coin for the March of Dimes commemorative set, and the 2014 proof silver and gold Kennedy Half Dollar commemorative set.

The facility still stores mostly gold bullion, second only to Fort Knox. All American Eagle proof and uncirculated commemoratives in bullion are produced by the West Point Mint Facility along with the American Buffalo gold coins.

Finally...

Mint marks were suspended in 1965 through 1967 for all U.S. Mint coinage to preserve coin circulation during the time silver was being removed from coins overall. Beginning in 1968, all mint marks were struck on the obverse (the face or 'heads' of the coin).

Altogether there were nine official United States Mints since the Coinage Act of 1792. Of the nine, only four remain as active United States Mints. Philadelphia, Denver and San Francisco strike all manner of legal tender circulating coins consisting of the penny, nickel, dime, quarter, half dollar and $1 coin, nearly 15 billion coins minted in 2017 worth nearly $963 million, not counting commemoratives from the West Point Mint Facility, the fourth operating Mint.

All that production is a far cry from the first strike of 11,178 copper and silver coins in 1793, all hand pressed at the time, and struck from borrowed silver.

Sources:

Jasper.com - Click to see the original article with photos.

Bucki, James,  "The Coinage of the United States"   November 24, 2018, thesprucecrafts.com

Jordan, Louis,   "The Comparative Value of Money Between Britain and the Colonies", University of Notre Dame, Department of Special Collections, coins.nd.edu.com, undated

Littleton's Illustrated Guide,  "Mint Marks on Regular-Issue U.S. Coins", undated

Taylor, Sol,  "The First Coins of the USA", May 19 2007, SCVhistory.com

United States Mint,  "Collecting Basics: Mint Marks" ,  undated

US-Mint.info,  "US Mint History Since 1792" ,  undated

Wikipedia.com,  "United States Mint", undated